Accurately determining the solubility of ethane in oil‐based mud is crucial for assessing the severity of gas kicks and implementing appropriate well control procedures. The key factors influencing the solubility of ethane gas in oil‐based drilling fluids include the content of base oil, pressure, temperature, and the viscosity of the drilling fluid. This study aims to test the solubility of high‐purity ethane in oil‐based mud under simulated downhole conditions in a 5000 m deep well. The test covers a temperature range of 40–140°C and a partial pressure range of 0.17–5.92 MPa. The effects of temperature, pressure, base oil content, and drilling fluid viscosity on the solubility of ethane are analyzed using various experimental data processing methods. The results show that the variation in ethane solubility with pressure and temperature is nearly linear within the specified ranges. Furthermore, the impact of pressure (1.24–2.78%/MPa) on solubility is approximately 50 times greater than that of temperature (−0.013 to −0.049%/°C) in oil‐based drilling mud. Additionally, ethane's solubility decreases as the drilling fluid's viscosity increases. The ethane solubility in 80% and 90% oil‐based muds is roughly 1.6 times and 2.0 times higher than in 70% oil‐based mud under the same testing conditions. Models for predicting ethane solubility have been developed using screening procedures and statistical regression. These models can be incorporated into gas–liquid flow models to analyze flow behavior during gas kicks.

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复杂油气井筒环境乙烷在油基泥浆中溶解特性实验研究

准确测定乙烷在油基泥浆中的溶解度对于评估气涌的严重程度和实施适当的井控程序至关重要。影响乙烷气体在油基钻井液中溶解度的关键因素包括基础油含量、压力、温度和钻井液粘度。本研究旨在模拟5000 m深井的井下条件下测试高纯度乙烷在油基泥浆中的溶解度。测试温度范围为40-140°C，分压范围为0.17-5.92 MPa。采用多种实验数据处理方法，分析了温度、压力、基础油含量、钻井液粘度对乙烷溶解度的影响。结果表明，乙烷溶解度随压力和温度的变化在指定范围内几乎呈线性。此外，在油基钻井泥浆中，压力（1.24-2.78%/MPa）对溶解度的影响大约是温度（-0.013至-0.049%/°C）的50倍。此外，乙烷的溶解度随着钻井液粘度的增加而降低。在相同的测试条件下，乙烷在80%和90%油基泥浆中的溶解度大约是70%油基泥浆中的1.6倍和2.0倍。已经使用筛选程序和统计回归开发了预测乙烷溶解度的模型。这些模型可以合并到气液流动模型中，以分析气涌期间的流动行为。